Desertification is the process of land degradation in arid, semi-arid and dry sub-humid areas resulting from factors such as climate change and human activities, according to the United Nations Convention to Combat Desertification. This definition is binding on states … signatories, means an irreversible decline in the productivity of terrestrial ecosystems due to overexploitation or inadequate management.
The agreement stipulates that combating desertification includes preventing and reducing degradation, rehabilitating damaged lands and restoring desertified areas, in addition to mitigating the effects of drought through forecasting and reducing exposure to drought. Likewise, it defines key concepts such as land, degradation and damaged areas, covering vital productive systems and ecological processes in areas with low relationship between rainfall and evapotranspiration.
In this context, the new Atlas of Desertification in Spain provides a detailed vision of the scope and development of this phenomenon in our territory. A project coordinated by researchers Jorge Olsina Cantos, Professor of Regional Geographic Analysis at the University of Alicante, and Jaime Martínez Valderrama, Scientist at the Experimental Station for Arid Zones of the Superior Council for Scientific Research (CSIC). Both researchers explained that desertification is one of Spain’s main environmental problems and that its “intensity and extent are increasing due to climate change and the unsustainable use of natural resources.” For this reason, they point out, “Mapping this complex process and the different variables involved is the first step to designing effective solutions.”
The origins of this project, called the Atlas, go back to the publication of the Global Atlas of Desertification in 2018, a work that deliberately avoided including global or regional mapping as the scientific community considered that existing methodologies at the time did not allow to rigorously address the problem. This decision opened a field of research that generated a political need. In response, the Government of Spain, in approving its National Strategy to Combat Desertification, has committed to developing new maps to replace those that are already outdated.
Advanced methodology
“With this background, the Atlas Project has compiled information on multiple aspects related to the problem, consulted the opinions of more than 40 experts and developed a cutting-edge methodology to overcome the mapping problems raised by AMD,” explain Jorge Olsina and Jaime Martínez.
In accordance with this definition of the United Nations Convention to Combat Desertification, highlighted by the study coordinators, the Atlas of Desertification in Spain is organized into three parts: maps for understanding desertification, a map of desertification in Spain, and case studies.
The atlas includes 66 maps that address six topics related to desertification: climate, water, soil, forest cover, biodiversity, and society. “Most of them are already existing maps and the added value was to provide them with a narrative linking them to the problem of desertification,” the coordinators explain. ATLAS also created some of its own maps, such as the population living in arid regions or the ecological footprint of food waste.
Machine learning
The main goal of the project was to prepare maps of degradation and desertification in Spain. To do this, the Random Forest algorithm, a supervised learning method that relies on a combination of multiple predictive models to improve accuracy compared to a single model, was implemented and trained. This algorithm includes five indicators of degradation: groundwater, wetlands, land condition, and indicators of Sustainable Development Goal 15.3.1, which measures the proportion of degraded land compared to the total area. The results showed that degradation affects 43.3% of the region, and desertification in arid areas reaches 60.9% of these areas, with an area of 206,203 square kilometers.
Led by several experts, the project explored 16 landscapes or conditions associated with desertification. “The goal was to delve into the various nuances surrounding this elusive concept, revealing what desertification is and is not, and the intermediate states that may or may not develop toward desertification,” Olsina and Martínez Valderrama detail.
The current context of climate change, which in Spain includes a gradual rise in temperatures and more erratic rainfall, does not contribute to improving the situation, quite the opposite. “We face some of our country’s most significant environmental challenges in the coming decades,” the authors concluded.
The Altas project is supported by the Biodiversity Foundation of the Ministry of Ecological Transition and Demographic Challenge (MITECO) within the framework of the Recovery, Transformation and Resilience Plan, funded by the European Union – NextGenerationEU.